This proposed research is to draw single molecules of denatured proteins through a small pore, a solid state nanopore in silicon nitride membrane, that is integral to a sensitive detector. The solid state nanopore detector is designed to guarantee that driven by electric field, each polypeptide traverses the nanopore in sequencial, single file order. The translocation of each polypeptide will induce a transient electronic signal, a current blockade in the detector. The research goal is to develop the nanopore technique to record single polypeptide translocations by measuring the current blockades, probe the peptide's fundamental properties including their length, diameter, secondary structure, charge, and eventually the amino acid sequence at high speed, high resolution, and low cost. The specific aims are: 1. Develop single channel recordings of polypeptide chains translocating through solid state nanopores driven by electric field in aqueous ionic solution. Such recordings will be used to achieve an electronic read-out of the fundamental properties of polypeptide chains. Study how the electronic signals are related to these fundamental molecular properties of interest. 2. Develop reliable control over the thickness, chemical activity, electrical conduction and noise properties of solid state nanopores compatible with the requirements of single protein sensing. 3. Study and test the appropriate temperature, pH, bias voltage and nanopore size conditions for optimize the process of amino acid chain translocation and identification through solid state nanopore sensors. 4. Develop data analysis software and statistical models to interpret nanopore electronic signals. If the research goals proposed here are reached, a high-throughput device that can probe and directly "read" electronically, at the single molecule level, the size, charge, folding, and sequence of proteins, will dramatically alter the pace of biology and medical science. The development of high throughput nanopore probes of the molecular and atomic characteristics of single peptide chains, and the fundamental understanding that will make development of such probes possible, would revolutionize functional genomics, and proteomics.